Hemingray-17 Clear Vintage Glass Insulator
This common toll style replaced the earlier No.16 style (CD 121) in the 1920's. These were produced in mass quantities, so most are very common. Aqua, Hemingray Blue, and Ice Blue pieces were manufactured until c.1938. Afterwards, all CD 122's produced were clear or straw.
Insulator diameter: 2.75 inches
Glass insulators were first produced in the 1850's for use with telegraph lines. As technology developed insulators were needed for telephone lines, electric power lines, and other applications. In the mid 1960's a few people began collecting these antique glass insulators. Today there are over 3,000 insulator collectors.
All glass pintype insulators are classified in what is called the “CD Numbering” system of identification. This system was created and used by N.R. “Woody” Woodward, an early pioneer, researcher and author in the field of collecting glass insulators. The CD (Consolidated Design) numbers basically identify insulators by their shape and profile, regardless of exact embossed markings, glass color, or base type.